STEP 3: Trace contours with a marching cubes algorithm.

• Subdivide the 3D space into cubes.
  
• Consider only cubes that are near the data
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
• For each vertex of the cubical lattice, push the point onto the surface by essentially projecting it onto the nearest tangent plane.
  
• Remove degenerate traingles with a post-processing edge collapsing algorithm.